sass-loader

Compiles Sass to CSS
授权协议 MIT License
开发语言 JavaScript
所属分类 Web应用开发、 常用JavaScript包
软件类型 开源软件
地区 不详
投 递 者 赵嘉悦
操作系统 跨平台
开源组织
适用人群 未知
 软件概览

tests

sass-loader

Loads a Sass/SCSS file and compiles it to CSS.

Getting Started

To begin, you'll need to install sass-loader:

npm install sass-loader sass webpack --save-dev

sass-loader requires you to install either Dart Sass or Node Sass on your own (more documentation can be found below).

This allows you to control the versions of all your dependencies, and to choose which Sass implementation to use.

ℹ️ We highly recommend using Dart Sass.

Node Sass does not work with Yarn PnP feature and doesn't support @use rule.

Chain the sass-loader with the css-loader and the style-loader to immediately apply all styles to the DOM or the mini-css-extract-plugin to extract it into a separate file.

Then add the loader to your Webpack configuration. For example:

app.js

import "./style.scss";

style.scss

$body-color: red;

body {
  color: $body-color;
}

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          // Creates `style` nodes from JS strings
          "style-loader",
          // Translates CSS into CommonJS
          "css-loader",
          // Compiles Sass to CSS
          "sass-loader",
        ],
      },
    ],
  },
};

Finally run webpack via your preferred method.

Resolving import at-rules

Webpack provides an advanced mechanism to resolve files.

The sass-loader uses Sass's custom importer feature to pass all queries to the Webpack resolving engine.Thus you can import your Sass modules from node_modules.

@import "bootstrap";

Using ~ is deprecated and can be removed from your code (we recommend it), but we still support it for historical reasons.Why can you remove it? The loader will first try to resolve @import as a relative path. If it cannot be resolved, then the loader will try to resolve @import inside node_modules.

Prepending module paths with a ~ tells webpack to search through node_modules.

@import "~bootstrap";

It's important to prepend it with only ~, because ~/ resolves to the home directory.Webpack needs to distinguish between bootstrap and ~bootstrap because CSS and Sass files have no special syntax for importing relative files.Writing @import "style.scss" is the same as @import "./style.scss";

Problems with url(...)

Since Sass implementations don't provide url rewriting, all linked assets must be relative to the output.

  • If you pass the generated CSS on to the css-loader, all urls must be relative to the entry-file (e.g. main.scss).
  • If you're just generating CSS without passing it to the css-loader, it must be relative to your web root.

You will be disrupted by this first issue. It is natural to expect relative references to be resolved against the .sass/.scss file in which they are specified (like in regular .css files).

Thankfully there are a two solutions to this problem:

  • Add the missing url rewriting using the resolve-url-loader. Place it before sass-loader in the loader chain.
  • Library authors usually provide a variable to modify the asset path. bootstrap-sass for example has an $icon-font-path.

Options

Name Type Default Description
implementation {Object|String} sass Setup Sass implementation to use.
sassOptions {Object|Function} defaults values for Sass implementation Options for Sass.
sourceMap {Boolean} compiler.devtool Enables/Disables generation of source maps.
additionalData {String|Function} undefined Prepends/Appends Sass/SCSS code before the actual entry file.
webpackImporter {Boolean} true Enables/Disables the default Webpack importer.
warnRuleAsWarning {Boolean} false Treats the @warn rule as a webpack warning.

implementation

Type: Object | StringDefault: sass

The special implementation option determines which implementation of Sass to use.

By default the loader resolve the implementation based on your dependencies.Just add required implementation to package.json (sass or node-sass package) and install dependencies.

Example where the sass-loader loader uses the sass (dart-sass) implementation:

package.json

{
  "devDependencies": {
    "sass-loader": "^7.2.0",
    "sass": "^1.22.10"
  }
}

Example where the sass-loader loader uses the node-sass implementation:

package.json

{
  "devDependencies": {
    "sass-loader": "^7.2.0",
    "node-sass": "^5.0.0"
  }
}

Beware the situation when node-sass and sass were installed! By default the sass-loader prefers sass.In order to avoid this situation you can use the implementation option.

The implementation options either accepts sass (Dart Sass) or node-sass as a module.

Object

For example, to use Dart Sass, you'd pass:

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              // Prefer `dart-sass`
              implementation: require("sass"),
            },
          },
        ],
      },
    ],
  },
};

String

For example, to use Dart Sass, you'd pass:

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              // Prefer `dart-sass`
              implementation: require.resolve("sass"),
            },
          },
        ],
      },
    ],
  },
};

Note that when using sass (Dart Sass), synchronous compilation is twice as fast as asynchronous compilation by default, due to the overhead of asynchronous callbacks.To avoid this overhead, you can use the fibers package to call asynchronous importers from the synchronous code path.

We automatically inject the fibers package (setup sassOptions.fiber) for Node.js less v16.0.0 if is possible (i.e. you need install the fibers package).

Fibers is not compatible with Node.js v16.0.0 or later (see introduction to readme).

package.json

{
  "devDependencies": {
    "sass-loader": "^7.2.0",
    "sass": "^1.22.10",
    "fibers": "^4.0.1"
  }
}

You can disable automatically injecting the fibers package by passing a false value for the sassOptions.fiber option.

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              implementation: require("sass"),
              sassOptions: {
                fiber: false,
              },
            },
          },
        ],
      },
    ],
  },
};

You can also pass the fiber value using this code:

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              implementation: require("sass"),
              sassOptions: {
                fiber: require("fibers"),
              },
            },
          },
        ],
      },
    ],
  },
};

sassOptions

Type: Object|FunctionDefault: defaults values for Sass implementation

Options for Dart Sass or Node Sass implementation.

ℹ️ The charset option has true value by default for dart-sass, we strongly discourage change value to false, because webpack doesn't support files other than utf-8.

ℹ️ The indentedSyntax option has true value for the sass extension.

ℹ️ Options such as data and file are unavailable and will be ignored.

We strongly discourage change outFile, sourceMapContents, sourceMapEmbed, sourceMapRoot options because sass-loader automatically sets these options when the sourceMap option is true.

ℹ️ Access to the loader context inside the custom importer can be done using the this.webpackLoaderContext property.

There is a slight difference between the sass (dart-sass) and node-sass options.

Please consult documentation before using them:

Object

Use and object for the Sass implementation setup.

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              sassOptions: {
                indentWidth: 4,
                includePaths: ["absolute/path/a", "absolute/path/b"],
              },
            },
          },
        ],
      },
    ],
  },
};

Function

Allows to setup the Sass implementation by setting different options based on the loader context.

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              sassOptions: (loaderContext) => {
                // More information about available properties https://webpack.js.org/api/loaders/
                const { resourcePath, rootContext } = loaderContext;
                const relativePath = path.relative(rootContext, resourcePath);

                if (relativePath === "styles/foo.scss") {
                  return {
                    includePaths: ["absolute/path/c", "absolute/path/d"],
                  };
                }

                return {
                  includePaths: ["absolute/path/a", "absolute/path/b"],
                };
              },
            },
          },
        ],
      },
    ],
  },
};

sourceMap

Type: BooleanDefault: depends on the compiler.devtool value

Enables/Disables generation of source maps.

By default generation of source maps depends on the devtool option.All values enable source map generation except eval and false value.

If a true the sourceMap, sourceMapRoot, sourceMapEmbed, sourceMapContents and omitSourceMapUrl from sassOptions will be ignored.

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          {
            loader: "css-loader",
            options: {
              sourceMap: true,
            },
          },
          {
            loader: "sass-loader",
            options: {
              sourceMap: true,
            },
          },
        ],
      },
    ],
  },
};

In some rare cases node-sass can output invalid source maps (it is a node-sass bug).

In order to avoid this, you can try to update node-sass to latest version or you can try to set within sassOptions the outputStyle option to compressed.

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              sourceMap: true,
              sassOptions: {
                outputStyle: "compressed",
              },
            },
          },
        ],
      },
    ],
  },
};

additionalData

Type: String|FunctionDefault: undefined

Prepends Sass/SCSS code before the actual entry file.In this case, the sass-loader will not override the data option but just prepend the entry's content.

This is especially useful when some of your Sass variables depend on the environment:

String

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              additionalData: "$env: " + process.env.NODE_ENV + ";",
            },
          },
        ],
      },
    ],
  },
};

Function

Sync
module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              additionalData: (content, loaderContext) => {
                // More information about available properties https://webpack.js.org/api/loaders/
                const { resourcePath, rootContext } = loaderContext;
                const relativePath = path.relative(rootContext, resourcePath);

                if (relativePath === "styles/foo.scss") {
                  return "$value: 100px;" + content;
                }

                return "$value: 200px;" + content;
              },
            },
          },
        ],
      },
    ],
  },
};
Async
module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              additionalData: async (content, loaderContext) => {
                // More information about available properties https://webpack.js.org/api/loaders/
                const { resourcePath, rootContext } = loaderContext;
                const relativePath = path.relative(rootContext, resourcePath);

                if (relativePath === "styles/foo.scss") {
                  return "$value: 100px;" + content;
                }

                return "$value: 200px;" + content;
              },
            },
          },
        ],
      },
    ],
  },
};

webpackImporter

Type: BooleanDefault: true

Enables/Disables the default Webpack importer.

This can improve performance in some cases. Use it with caution because aliases and @import at-rules starting with ~ will not work.You can pass own importer to solve this (see importer docs).

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              webpackImporter: false,
            },
          },
        ],
      },
    ],
  },
};

warnRuleAsWarning

Type: BooleanDefault: false

Treats the @warn rule as a webpack warning.

ℹ️ It will be true by default in the next major release.

style.scss

$known-prefixes: webkit, moz, ms, o;

@mixin prefix($property, $value, $prefixes) {
  @each $prefix in $prefixes {
    @if not index($known-prefixes, $prefix) {
      @warn "Unknown prefix #{$prefix}.";
    }

    -#{$prefix}-#{$property}: $value;
  }
  #{$property}: $value;
}

.tilt {
  // Oops, we typo'd "webkit" as "wekbit"!
  @include prefix(transform, rotate(15deg), wekbit ms);
}

The presented code will throw webpack warning instead logging.

To ignore unnecessary warnings you can use the ignoreWarnings option.

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          "css-loader",
          {
            loader: "sass-loader",
            options: {
              warnRuleAsWarning: true,
            },
          },
        ],
      },
    ],
  },
};

Examples

Extracts CSS into separate files

For production builds it's recommended to extract the CSS from your bundle being able to use parallel loading of CSS/JS resources later on.

There are two possibilities to extract a style sheet from the bundle:

webpack.config.js

const MiniCssExtractPlugin = require("mini-css-extract-plugin");

module.exports = {
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          // fallback to style-loader in development
          process.env.NODE_ENV !== "production"
            ? "style-loader"
            : MiniCssExtractPlugin.loader,
          "css-loader",
          "sass-loader",
        ],
      },
    ],
  },
  plugins: [
    new MiniCssExtractPlugin({
      // Options similar to the same options in webpackOptions.output
      // both options are optional
      filename: "[name].css",
      chunkFilename: "[id].css",
    }),
  ],
};

Source maps

Enables/Disables generation of source maps.

To enable CSS source maps, you'll need to pass the sourceMap option to the sass-loader and the css-loader.

webpack.config.js

module.exports = {
  devtool: "source-map", // any "source-map"-like devtool is possible
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [
          "style-loader",
          {
            loader: "css-loader",
            options: {
              sourceMap: true,
            },
          },
          {
            loader: "sass-loader",
            options: {
              sourceMap: true,
            },
          },
        ],
      },
    ],
  },
};

If you want to edit the original Sass files inside Chrome, there's a good blog post. Checkout test/sourceMap for a running example.

Contributing

Please take a moment to read our contributing guidelines if you haven't yet done so.

CONTRIBUTING

License

MIT

  • 1、使用save会在package.json中自动添加。 npm install node-sass --save-dev npm install sass-loader --save-dev 注:通常使用npm安装会出现以下报错,安装失败。(网路问题) 可以通过淘宝的npm镜像安装node-sass,解决以上问题。 npm install -g cnpm --registry=https://r

  • 目录 使用scss报错 当前node-sass、sass-loader版本 测试 步骤一 步骤二 解决方案 解决node-sass问题 node和node-sass版本关系 这篇文章主要写node、node-sass、sass-loader三者引起的兼容问题。 使用scss报错 为什么要写这篇文章,安装最新版sass运行报错了。 纳尼,最新版的既然不兼容。 来看看错误提示 ERROR Fail

  • 本篇文章将介绍 前端开发中webpack常用的node-sass、sass-loader、style-loader、less-loader、style-loader等区别作用; 讲解之前先要介绍一下node? 1,前端开发人员为什么要安装Node 一,传统的JavaScript 传统的js是运行在浏览器上的,因为浏览器内核分为两个部分:渲染引擎---渲染HTML和CSS; JavaScript 引

  •   太难了,两天没有学习了,这个问题卡了很久,差点就放弃了,今天终于解决了,继续学习Vue! 报错信息1: ERROR Failed to compile with 6 errors 7:45:21 PM error in .

  • sass-loader兼容性问题 PS E:\dome\automated-test-platform-vue2> npm install sass@~1.32 sass-loader@10.1.1 deepmerge -D npm ERR! code ERESOLVE npm ERR! ERESOLVE unable to resolve dependency tree npm ERR! npm

  • sass是一门css预处理器语言 node-sass是帮助nodejs这个平台,连接libSass(用来编译sass语言的预处理器) sass-loader在实现安装了node-sass的基础上,使用webpack时,将sass这门语言写的样式文件,编译成css文件

  • node版本:16.18.1 1.卸载node-sass      npm uninstall node-sass 2.安装node-sass(当前本地node版本:16.18.1)      npm i node-sass@6.0.1 sass-loader@10.2.0 --save-dev(查询官网node-sass对应版本为v6+) 3.安装less-loader     npm inst

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